| 摘要 |
PURPOSE:To suppress fluctuation of voltage to be applied on a load by arranging two voltage detectors, and using one voltage detector under non-load operation of an inverter, whereas using the other voltage detector under power supply operation of the inverter for the control of the output voltage of the inverter. CONSTITUTION:Current is fed to a load 8 from a commercial power source 2 via a second AC switch 7. Between a CVCF inverter 4 and a first AC switch 6, a first voltage detector 11 is set, and on the load side of the first AC switch 6, a second voltage detector 21 is set. Besides, a change-over switch 22 for switching the voltage detectors 11, 21 is set. While the current is fed to the load 8 from the CVCF inverter 4, the second voltage detector 21 is selected. In other words, by the inverter 4, load voltage is controlled to come to a specified value. Besides, when commercial power is being fed, the first voltage detector 11 is selected, and the output voltage of the inverter 4 under non-load operation is sustained at a specified value thus preparing against service interruption. |
